Heat-exchange apparatus including cyclone separators



Aug. 13, 1957 K. J. SYLVEST HEAT-EXCHAR'GE APPARATUS INCLUDING CYCLONE SEPARATORS Filed 001;. 12, 1955 4 Sheets-Sheet 1 Aug. 13, 1957 K. J. SYLVEST HEAT-EXCHANGE APPARATUS INCLUDING CYCLONE SEPARATORS Filed Oct. 12, 1955 4 Sheets-Sheet 2 Aug. 13, 1957 K. J. SYLVEST 2,302,280

HEAT-EXCHANGE APPARATUS INCLUDING CYCLONE SEPARATORS Filed Oct. 12, 1955 4 Sheds-Sheet s ATTORNEYS Aug. 13, 1957 K. J. SYLVEST 2,802,280

HEAT- -EXCHANGE APPARATUS INCLUDING CYCLONE SEPARATORS Filed Oct. 12, 1955 4 Sheets-Sheet 4 FIG. 9

ATTORNEY United States Patent HEAT-EXCHANGE APPARATUS INCLUDING CYCLONE SEPARATORS Karl Jens Sylvest, Copenhagen, Denmark, assignon to F. L. 'Smidth & C0., New York, N. Y., a corporation of New Jersey Application October 12, 1955, Serial No. 540,130

Claims priority, application Great Britain October 13, 1954 11 Claims. (CI. 34-57) This invention relates to apparatus for the exchange of heat between gases and finely divided material in suspension therein and of the type, in which a plurality of cyclone separators are employed in series with the solids separated in the later separators being introduced into the gas streams traveling toward the preceding separators. More particularly, the invention is concerned with a heatexchange apparatus of the type specified, in which a novel arrangement of the separators is employed with resultant reductions both in the overall height of the apparatus and in heat loss by radiation.

Heat-exchange apparatus of the multiple cyclone separator type has been commonly constructed heretofore with the separators disposed at successively higher levels in the direction of gas flow in orderthat the separated particles can travel through the apparatus by gravity. Such an apparatus'may have so great an overall height that space limitations may prevent its use at a particular location and, in an alternative construction, the total height of the apparatus is reduced by causing the pipes leading to the separator inlets to dip downwardly and introducing the separated solids from the separators into the low sections of the piping. While this expedient saves space, the total height of the installation is still substantial.

In all forms of heat exchange apparatus of the multiple cyclone separatortype, in which solid particles are heated by hot gases, there is a substantial loss of heat by radiation from the separators because of their large surface area; While such loss can be reduced by covering the separators with insulation, the insulation is expensive to install and it does not eliminate the heat loss entirely.

The present invention is directed to the provision of heat-exchange apparatus including a plurality of cyclone separators arranged in series, in which a reduction in the total height of the apparatus and in the heat loss from the separators is eifected by mounting at least one of the separatorswholly or partly within another. When the apparatus includes two separators, the inner separator may be either the first or second traversed by the gases and, when more than two separators are employed, the

separators may be disposed in telescoped relation in a single assembly, or the apparatus may be made up of a plurality of pairs of telescoped separators, or other arrangements may be used.

For a better understanding of the invention, reference may be made to the accompanying drawings, in which Fig. 1 is a somewhat diagrammatic side elevational view with parts broken away of one form of the apparatus;

Fig. 2 is a sectional view on the line 2-2 of Fig. 1;

Figs. 3'8, inclusive, are somewhat diagrammatic side elevational views with parts broken away of modified forms of the apparatus; and

Fig. 9 is a sectional view on the line '99 of Fig. 8.

'The heat-exchange apparatus of the invention in the form illustrated in Fig. 1 is employed in association with a kiln 10, the upper end of which enters a smoke chamber 11. The hot gases from the kiln pass through the chamber and through a riser pipe 12 to the tangential inlet of a cyclone separator 13 having the usual conical lower end 14. A pipe 15 containing a rotary gate valve 16 conduets the separated solids from the separator 13 into a second pipe 17, which extends through the smoke chamber 11 and enters the upper end of the kiln 10. Separator 13 has an outlet for gases through its top and the gases are conducted away through a pipe 18.

A smaller separator 19 is disposed wholly within separator 13 coaxially therewith and the inner separator has a tangential inlet, to which pipe 18 leads. The pipe has a section 18:: crossing the space between the two separators and, since this section lies in the path of the whirling gases, it has the streamlined cross-sectional shape shown in Fig.2. The inner separator has a conical lower end 24) with an outlet for separated solids, and a pipe 21 containing a rotary valve 22 conducts the separated solids to pipe 12 and discharges the solids into the path of the gases traveling upward through that pipe.

The inner separator 19 has an outlet at its top for gases and a pipe 23 extends upwardly through the outlet and through pipe 18 to conduct the gases to a filter 24. The outlet from the filter is connected by a pipe 25 to the inlet of a blower 26, the outlet of which is connected by a pipe 27 to a stack (not shown). The filter has an outlet for separated solids at its bottom and pipe 17 leads from the outlet. The pipe contains a rotary gate valve 22%. V

The raw material to be heated is supplied from a storage bin, the lower end of which is shown at 29, and the bin has a bottom outlet, from which a connection 30 leads into pipe 13. In the construction illustrated, the connection is a screw conveyor, the screw shaft of which has a pulley 31 driven by a drive belt 32.

in the operation of the apparatus illustrated in Figs. -1 and 2, the hot gases from the kiln enter the smoke chamber 11 and then travel through the riser pipe 12 and enter the first or outer separator 13 through its inlet. The gases travel with a circular movement through the separator and the solid particles are thrown outwardly against the separator wall by centrifugal action and collect in the conical lower end of the separator whence they are discharged through pipe 15 into pipe 17 leading into the kiln. The rotary gate valve 16 prevents gases from the kiln traveling back through pipe 15 into the separator. The gases leaving the outer separator 13 enter the second or inner separator 19 through pipe 18 and separated solids leaving the outlet at the lower end of the inner separator travel through pipe 21 and rotary gate valve 22 to be discharged into the path the gases rising through pipe 12. Thegases issuing from the inner separator enter the filter 24 and the separated dust collected in the filter is conducted through the pipe 17 into the kiln. The gases freed of dust then pass through blower 26 and are discharged into the stack. Material to be heated is continuously introduced from the container 29 into the pipe 18 and takes up heat from the gases while traveling in suspension therein into the inner separator 19. The separated solids leaving separator 19 and entering the pipe 12 again take up heat from the gases while traveling in suspension to the outer separator 13. The material leaving the'outer separator and combined with the dust .from filter 24 is at a relatively high temperature as it enters the kiln.-

In the apparatus of Fig. 1, the outer separator 13 is provided with the usual insulation. However, the inner separator is insulated by the gases between the two separators and little or no insulation on the inner separator is required. 7

The apparatus shown in Fig. 3 is generally similar to that shown in Fig. 1, except for a reversal of the position of the separators. In the Fig. 3 construction, the

gases issuing from the kiln 33 pass through smoke box 34 and enter riser pipe 35 leading to the tangential inlet of a separator 36, which lies wholly within an outer separator 37 and is coaxial therewith. Pipe 35 has a section of streamlined shape in the space between the separators. Separator 36 has a bottom outlet, from which a pipe 38 leads to a pipe 39, the latter extending through the smoke box and discharging into the upper end of the kiln. The inner separator also has a gas outlet at its top, from which a pipe 40 leads to the tangential inlet of the outer separator 37. Separator 37 has a bottom outlet, from which a pipe 41 leads into the riser pipe 35, and it also has a gas outlet at its top, from which a pipe 42 leads. Pipe 42 encloses a section of the pipe 40 leading from the gas outlet of the inner separator and may lead to a blower discharging into the atmosphere, but preferably leads to a filter similar to filter 24 and having a bottom outlet connected to pipe 39.

In the Fig. 3 construction, the raw material is contained within a bin 43 having a bottom outlet with a connection 44 leading into pipe 40. The connection may be a screw conveyor similar to conveyor 30.

The apparatus of Fig. 3 functions in the same manner as that shown in Fig. 1, except that the first separator entered by the gases leaving the smoke chamber is the inner one. As the inner separator contains the gases at the highest temperature and is insulated by the gases in the outer separator, there is less loss of heat by radiation in the Fig. 3 construction than in that shown in Fig. 1, assuming the same solid insulation is present in both forms of apparatus.

The apparatus shown in Fig. 4 is similar to that shown in Fig. 3, except that the separators are only partially telescoped. The gases issuing from kiln 45 enter the enlarged lower end 46a of the riser pipe 46 and enter the separator 47 through its tangential inlet. The separator extends downwardly through the top of an outer separator 48 and the inner separator 47 has a bottom outlet, from which the separated solids are conducted through a connection leading into the upper end of the kiln. The connection includes a pipe 49 connected to the outlet, a screw conveyor 50, and a pipe 51 leading from the conveyor into the kiln.

The inner separator 47 has a gas outlet at its top, from which a pipe 52 leads to the tangential inlet of the outer separator 48. The outer separator has an outlet at its bottom for solids, which are conducted through a connection 53 into pipe 46, the connection shown being a screw conveyor. The conveyors 50 and 53 both advance the material and prevent flow of gases backward into the respective separators.

The outer separator 48 has an outlet for gases, which takes the form of a casing 54 secured to and enclosing the lower end of inner separator 47 and thus closed at its top. A pipe 55 leads from the casing and the pipe has a section 55a of streamlined form between the casing and the wall of the outer separator. Pipe 55 may lead to a blower or to a filter, as in the Fig. 1 construction.

The raw material to be heated is contained within a bin, the lower end of which is shown at 56. The bin has a bottom outlet, from which connection 57, in the form of a screw conveyor, leads into pipe 52.

The apparatus of Fig. 4 functions in the same manner as those previously described and the apparatus has the advantage that, since the inner separator is only partially enclosed in the outer one, the operations of erecting the separators and of dismantling them for repairs are easier to carry out than in a construction, in which one separator is wholly within the other.

i The apparatus shown in Fig. is constructed to per form the heat exchange in more than two stages and the apparatus includes four separators arranged as twopairs with one member of. each pair partly within the other. The gases from the kiln 58 travel upwardly through pipe 59 having an enlarged lower section 59a and enter the outer separator 60 of the first pair through its inlet. The separator has an outlet at its bottom for solids, which are conducted through a connection into the upper end of the kiln, the connection including a pipe 61, a screw conveyor 62, and a pipe 63. The outer separator has a gas outlet including a casing 64 secured to the inner separator, and a pipe 65 leads from the casing to the inlet of the inner separator 66. The inner separator has a solids outlet at its bottom from which material is conducted through a connection into pipe 59, the connection including a pipe 67 and a screw conveyor 68. The inner separator has a gas outlet at its top, from which leads a pipe 69.

The second pair of separators includes an outer separator 70 having an inlet, to which pipe 69 leads, and this separator has a bottom outlet with a pipe 71 containing a rotary gate valve 72 and conducting the material into the gas stream flowing through pipe 65. Separator 70 also has a gas outlet including a casing 73 secured to the lower end of an inner separator 74 and a pipe 75 leads to the inlet of the inner separator. Separator 74 has a bottom outlet, from which the material is led through a connection into pipe 69, the connection including a pipe 76 and a screw conveyor 77. The gases leave separator 74 through a top outlet, from which a pipe 78 leads to a blower discharging to the atmosphere or, if preferred, to a filter similar to filter 24.

The raw material is contained in a bin, the lower end of which is shown at 79. A connection in the form of a screw conveyor 80 leads from the bottom outlet of the bin into pipe 75.

in the operation of the apparatus of Fig. 5, the hot gases leaving the kiln enter the outer separator 60 of the first pair carrying with them separated materials discharged from the inner separator 66 of that pair. The solids separated in the outer separator are discharged into the upper end of the kiln through the connection from the outlet of the outer separator and the gases from the outer separator enter the inner separator carrying with them in suspension the solids received from the outer separator 70 of the second pair. The gases leaving the inner separator 66 of the first pair enter separator 70 carrying with them solids received from the inner separator 74 of the second pair. Gases from the separator 70 enter the inner separator 74 carrying with them the raw material received from the bin 79. In the Fig. 5 apparatus, the material is heated in four stages, namely, while it is in suspension in the gases in pipes 75, 69, 65, and 59, and in the separators, and a good heat recovery is thus obtained.

The apparatus illustrated in Fig. 6 is employed for heat treatment in three stages and the gases used for the purpose are obtained from a rotary kiln 81 and travel upward through pipe 82 to the inlet of separator 83 having a bottom outlet, through which separated solids enter a connection leading into the upper end of the kiln. The connection includes a pipe 84 connected to the separator, a screw conveyor 85, and a pipe 86. The separator 83 has a gas outlet including a casing 87 and a pipe 88 extends from the interior of the casing out through the wall of the separator and to the inlet of an intermediate separator 89.

The separator 89 extends into separator 83 through the top of the latter and is coaxial therewith. At its lower end, separator 89 has an outlet for separated solids, which are conducted through a connection consisting of a pipe 99 and a screw conveyor 91 into pipe 82. Separator 89 has a gas outlet comprising a casing 92, from which a pipe 93 leads to the inlet of an inner separator 94 projecting into separator 89 through its upper end. Separator 94 has a bottom outlet, from which separated solids are conducted through a connection into that part of pipe 88 lying within casing 87, the connection including a screw conveyor 95 and a pipe 96. The shaft 97 of the screw conveyor extends upwardly and out of the top of separator 94. A pipe 98 leads gases from a gas outlet at the top of separator 94 to a blower or a filter.

Raw material is supplied to the apparatus of Fig. 6 from a container, the lower end of which is shown at 99. The container has a bottom outlet, from which the material discharged is conducted through a connection 100 into the interior of pipe 93, the connection in the apparatus illustrated being a screw conveyor.

In the operation of the apparatus shown in Fig. 6, the gases travel through the separators in succession and the material to be heated enters the gas stream flowing to the third separator or the one last in the series. The solids separated in the third separator are then introduced into the stream flowing to the second separator and the solids separated in the second separator are introduced into the stream flowing to the first separator. The material separated in the first separator is introduced into the kiln.

The apparatus shown in Fig. 7 is of the three-stage type and includes only a single pipe for transferring gases from one separator to the next. The apparatus is shown in use in connection with a kiln 101, the gases from which pass through a smoke chamber 102 and enter a pipe 103' leading to the inlet of an outer separator 104. This separator has a bottom outlet, from which a pipe 105 containing a rotary gate valve 106 conducts sepa rated material into the upper end of the kiln. The separator has a gas outlet including a casing 107 attached to the lower end of an intermediate separator 108 extending into separator 104 through its upper end. A pipe 109 leads from the interior of the casing to the inlet of the intermediate separator. Separator 108 has a bottom outlet, from which a pipe 110 containing a rotary gate valve 111 leads into the pipe 103. The gases leave separator 108 through a casing 112, the lower end of which serves as the outlet from separator Casing 112 extends out through the upper end of separator 108 and surrounds an inner separator 113 having an inlet 114 within the casing. Separator 113 has a bottom outlet, from which a connection leads separated material into that part of pipe 109 lying within casing 107, the connection including a screw conveyor 115 and a pipe 116. The separator 113 has a gas outlet at its top, from which a pipe 117 leads to a blower or a filter.

The raw material to be heated is contained within a bin, the lower end of which is indicated at 118, and a connection in the form of a screw conveyor 119 leads from the bottom of the bin into the upper end of separator 113.

The operation of the apparatus of Fig. 7 is similar to that of the apparatus of Fig. 6, but, in traveling from the intermediate separator to the inner separator, the gases pass between the inner separator and its surrounding casing 112 and do not travel through an exposed pipe. The apparatus of Fig. 7 thus functions with less heat loss than that shown in Fig. 6.

The apparatus shown in Fig. 8 includes four telescoped separators, of which the outer separator 120 receives gas from a rotary kiln 121 through a pipe 122. At its lower end, the separator has an outlet for separated solids, which are conducted through a connection including a screw conveyor 123 and a pipe 124 into the upper end of the kiln. The separator has a gas outlet, which includes a casing 125 secured to and surrounding the lower end of a separator 126, which projects into separator 120 through its upper end. A pipe 127 leads from an opening in the wall of the casing and conducts gases from separator 120 to the inlet of separator 126.

Separator 126 has an outlet at its lower end for discharge of separated solids, which are conducted through a pipe 128 to a screw conveyor 129 discharging into pipe 122. Separator 126 has a gas outlet, which ineludes a casing 130 surrounding and mounted on the lower end of a separator 131, which projects into separator 126 through its upper end. A pipe 132 leads from the interior of casing to the inlet of separator 131. The solids collected in the lower end of separator 131 are conducted from the separator outlet through a pipe 133 to a screw conveyor 134 discharging into pipe 127. The gases leave separator 131 through a casing 135, which extends into separator 131 through its top and encloses a separator 136 having an inlet 137 within the casing adjacent its upper end.

Separator 136 has an outlet at its lower end and solids leaving the separator travel through a connection including a screwconveyor 138 and a pipe 139 into that part of pipe 132 lying within casing 130. Separator 136 has a gas outlet at its top, from which a pipe 140 'leads to a blower or to a dust filter.

The material to be heated is contained within a bin, the lower end of which is shown at 141, and the material issuing from the bin enters a screw conveyor 142 dicharging into separator 136 at its top. Separator 136 carries a partition adjacent its inlet 137 leading to the inner wall of casing 136 to direct the gases rising through the casing to the inlet and separator 113 in the apparatus of Fig. 7 is preferably provided with a similar partition.

The forms of the apparatus illustrated are for heat exchange, in which finely divided material takes up heat from hot gases while carried in suspension therein. The apparatus may be used equally well for the cooling of finely divided material, inwhich event cool air or other gas enters the first separator in the series and the hot material is introduced into the apparatus at the point, at which the material is supplied from a bin in the forms of the apparatus shown.

In some instances, the gases available for heating the particles in the apparatus may be very high, as, for example, of a temperature of 1000 C., and, if such hot gases are led first into a separator lying within another one, the insulation of the inner separator by the gases contained in the outer one may be so eifective that the wall of the inner separator will reach a temperature higher than it can withstand. In such instances, the gases may be preliminarily reduced in temperature by including in the apparatus as the first separator in the series an ordinary cyclone separator'having its wall cooled by the surrounding atmosphere. The gases issuing from the first separator are then passed to the inner separator previously mentioned.

I claim:

1. A heat-exchange apparatus for transfer of heat between gases and finely divided material in suspension therein, which comprises at least two cyclone separators, one of the separators being mounted to be at least partly enclosed within the other with a space between the peripheral walls of the separators, each separator being complete in itself and having an inlet and separate outlets for gas and solids, a riser pipe leading to the inlet of the first separator for conducting a gas thereto, a pipe for conducting separated solids from the solids outlet of the first separator out of the apparatus, a pipe connecting the gas outlet of the first separator to the inlet of the second separator, a pipe for conducting separated solids from the solids outlet of the second separator into the riser pipe leading to the inlet of the first separator, a connection for conducting gas from the gas outlet of the second separator, a container for pulverulent material having a bottom outlet, and means for conducting material from the container outlet into the gas pipe leading to the inlet of the second separator.

2. The heat-exchange apparatus of claim 1, in which the pipe leading from the solids outlet of' the first separator and of the apparatus and the pipe for conducting separated solids from the solids outlet of the second separator with the riser pipe contain means for passing solids while preventing flow of gas into the separators.

3. The heat-exchange apparatus of claim 2, in which at least one of the means for passing solids is a conveyor.

4. The heat-exchange apparatus of claim 1, in which the first separator is at least partly enclosed within the second separator.

5. The heat-exchange apparatus of claim 1, in which the second separator lies within the first and the gas outlet of the first separator is connected to the inlet of the second separator by a pipe, part of which lies inside the first separator and is of streamlined cross-section.

6. The heat-exchange apparatus of claim 1, in which the first separator lies within the second and the gas outlet of the first separator is connected to the inlet of the second by a pipe having a part within and coaxial with the gas outlet of the second separator.

7 The heat-exchange apparatus of claim 1, in which the inner separator projects out through the top of the outer separator and the gas outlet of the outer separator includes a casing within the separator having an open lower end and a pipe leading from the interior of the casing through the separator side Wall.

8. The heat-exchange apparatus of claim 7, in which the separators are coaxial and the casing encircles the lower end of the inner separator and is mounted on the wall thereof.

9. A heat-exchange apparatus for transfer of heat between gases and pulverulent material in suspension thereon, which comprises a cyclone separator having a tangential gas inlet through its side wall near its top, a gas (.2 outlet through its top, and an outlet at its bottom for separated solids, a second cyclone separator enclosing the lower end of the first separator and having a tangential gas inlet through its side wall near its top and an outlet at its bottom for separated solids, and a casing surrounding and spaced from the side Wall of the first separator, the casing being closed at its upper end and having an open lower end serving as the gas outlet from the second separator.

10. The heat-exchange apparatus of claim 9, which includes a container for pulverulent material having an outlet and a connection for conducting material from the container outlet into the first separator through an opening in the top of the separator.

11. The heat-exchange apparatus of claim 10, in which the connection leading from the container outlet contains means for passing material while preventing flow of gas from the separator into the container.

References Cited in the file of this patent UNITED STATES PATENTS 688,810 Raymund Dec. 10, 1901 1,367,636 Sturtevant Feb. 8, 1921 1,934,41G Cummins Nov. 7, 1933 1,962,455 Montgomery June 12, 1934 1,968,862 Sturtevant Aug. 7, 1934 2,343,985 Lamoureaux Mar. 14, 1944 

